The present invention relates to a button fixing member and a button structure, and more specifically to a button fixing member made of a synthetic resin, which is used to fix, to a cloth, a button such as a female snap, a male snap, a decorative button and the like, and a button structure consisting of such a button fixing member and such a button.
When a button such as a female snap and the like is fixed to a cloth, a button fixing member is generally used, which comprises a disk-like base and a post protruding from the base and tapering. When a button is fixed to a cloth using such a button fixing member, the button attaching member is set on a lower die below the cloth as horizontally placed, and the button is held by an upper die above the cloth. After that, the upper die is lowered. Thereby, the post of the button attaching member pierces the cloth upwardly and then passes through a fixing opening of the button to stick out. By swaging an distal side part of the post by a punch in the upper die, the button is fixed onto the cloth.
The button fixing member made of a synthetic resin is generally produced by injection molding, where a melted thermoplastic resin is injected into a mold and then cooled and solidified therein. The post is required to be thickened to a certain extent (relatively large diameter) in order to obtain strength etc. needed on swaging. However, in injection-molded button fixing members, there is a problem that void (shrinkage cavity) easily arises in a relatively thick post. If a quantity of void arising is relatively large, the post would be broken or a force for fixing a button would not reach the expected value when a button is fixed to a cloth with the button fixing member. In addition, since there are variations in a quantity of void arising, there would be variations in a force for fixing a button. If a material temperature, a mold temperature, a cooling time, etc. are changed at the time of injection-molding so as not to generate void, shrinkage (contraction) will occur on the outer surface of a molded product, or production efficiency will be reduced.
In view of the problems as mentioned above, an object of the present invention is to provide a button fixing member and a button structure in which the post contains almost no void.